The present invention generally relates to medium processing apparatuses and more particularly to a medium processing apparatus capable of printing on various media and a medium positioning mechanism used in such a medium processing apparatus.
Today, an institution, typically a financial institution or a local government office, has to issue various types of certificates. In order to handle the complicated process of issuing these certificates, there is a need for a printing apparatus that is capable of printing various different documents such as a certificate or a bankbook that have various different sizes. In other words, there is a need of a printing apparatus that is capable of printing on various forms called hereinafter a "medium." The process of printing on such a medium will be referred to hereinafter as "processing."
As such a medium processing apparatus uses a general purpose printer for printing letters on a medium, it is necessary to align the medium with respect to the printer such that the medium is positioned in alignment with the range in which the printer is capable of printing. Such a positioning of the medium with respect to the printer is particularly important for a medium such as a bankbook that is inserted manually to the printer by inexperienced user.
In view of the foregoing, conventional medium processing apparatuses generally include a positioning mechanism for positioning the medium on which a printing is to be made such that the medium is aligned properly with respect to the printer in the printing apparatus.
Conventionally, the positioning mechanism used in such a medium processing apparatus has achieved the necessary positioning of the medium by aligning a lateral edge of the medium to a predetermined reference position of printing conducted by the printer. For example, the medium to be fed into the printer is urged to the left or right in the medium feed path such that a left edge or a right edge of the medium is aligned to the reference printing position of the printer.
In view of variously different sizes of the media to be processed by a medium processing apparatus, conventional medium processing apparatuses use such a positioning mechanism also in a feed path of the medium for feeding the medium to the printer. Typically, the medium is urged to the right edge of the feed path for achieving the desired positioning.
On the other hand, such an edge-reference feeding of medium, in which a medium is fed in the state that the medium is urged to the right or left edge of the feed path, tends to cause a problem in that the medium experiences a deformation or jamming as a result of friction caused between the medium and the right or left wall of the feed path to which the medium is urged during the feeding. In order to avoid this problem, recent medium processing apparatuses are going to adopt a center-reference feeding and printing process in which the medium is transported along a center of the feed path and the printing is made about a center-reference position set at the center of the area of printing.
In view of such a center-reference feeding and printing of the medium, there is a need for a medium positioning mechanism for positioning a medium in alignment with a center of the medium feed path.
Other than the foregoing problem, the conventional edge-reference feeding of a medium has a drawback in that, once the medium positioning mechanism is mounted on a medium processing apparatus in alignment with the general purpose printer inside the medium processing apparatus, there is no possibility for adjusting the reference position of medium feeding. Thus, it is not possible to replace the printer to a model other than the currently used one. Whenever the printer is to be replaced with a new printer, there is no choice but to use the same model of printer even when there are various new high-performance model models available.
In addition, the conventional edge-reference feeding process of a medium has a further drawback, in relation to the use of an arm for urging the medium to the right edge wall or left edge wall of the feed path, in that the medium tends to experience a deflection as a result of engagement of the arm from a lateral direction. The deflection of the medium becomes a particularly serious problem in the feed path in which the medium is transported in a flat state. In a flat state of the medium, it should be noted that the medium is particularly vulnerable to deflection when a lateral urging force is applied. The deflection occurring in a medium results in a jamming of the medium in the feed path.
Further, such a conventional medium positioning mechanism that uses an arm for urging the medium has a drawback in that the speed of the lateral positioning of the medium cannot be increased as desired. As the arm is moved laterally with a generally constant speed, such an increase in the speed of the arm would cause a severe deflection in the medium.
Thus, it has been necessary to set the moving speed of the arm to be substantially slower than the speed desired for high speed printing in the conventional medium positioning mechanism.